9 Computational, crystal structure and antimicrobial studies of directly synthesized dichloroethylenediaminecopper (II) complex Rakesh Kumar a *, Sangeeta Obrai a *, V K Joshi b ,Vikas Kumar b and Siyamak Shahab c * a Department of Chemistry, Dr B R Ambedkar National Institute of Technology, Jalandhar-144011 (Punjab) INDIA. ab Department of Plant Harvest & Technology, Dr Y S Parmar University of Horticulture and Forestry, Solan, Hima- chal Pradesh (INDIA). c Institute of Physical Organic Chemistry of National Academy of Sciences of Belarus. *E-mail: rakesh_nitj@yahoo.co.in Received: November 11, 2014; accepted December 23, 2014 Abstract: The computational calculations of [CuCl 2 (en)] complex in the gaseous phase has been carried out using MM3 and PM5 methods. First time, crystallographic structure deter- mination of directly synthesized dichloroethylenediamminecop- per (II) complex from copper metal has been reported here. A comparison of the crystallographic structure in the solid state and gaseous state with optimized molecular geometry has been also presented. An agreement has been found in the computa- tional analysis and the experimental observations. The theoreti- cal calculations of HOMO-LUMO energies have revealed that the charge transfer occur within the complex. Crystallograph- ically determined structure having dimensions: a = 6.795 (5) Å, b = 5.760 (5) Å, c = 8.223 (5) Å, β = 93. 841 (5)° with monocli- nic crystal system and P2 1 /m space group. The structure was refined by Fourier and full matrix least squares methods. The antimicrobial property of the present complex has also been screened against four bacterial strains. Supporting information: X-Ray, IR, Uv-vis, HOMO-LUMO diagram. Keywords: Computational calculations, Direct synthesis, Crys- tal structure, Copper, HOMO-LUMO, Antimicrobial activity. 1. INTRODUCTION In transition metal complexes, Cu(II) ions are well known for their importance in biological systems and also for their phar- macological values. Metal complexation can changes or increas- es the biological activity of organic ligands after coordination [1]. Cu(II) complexes are important because they offer various potential advantages as antimicrobial, antiviral, antiin- flammatory, antitumor agents, enzyme inhibitor, chemical nu- cleases [2,3], anticancer activity [4] and they also proved to be beneficial against several diseases like copper rheumatoid and gastric ulcers. The treatment with copper complexes produced remarkable pharmacological effects, which are not observed when the parent ligand or inorganic forms of copper is used. Many of copper complexes have been reported earlier which are effective to inhibit bacterial growth, fungal, yeast, algal, myco- plasma and viral growth as well as to cause the death of these organisms [5-13]. Copper complexes with aliphatic and hetero- cyclic amines are also known to catalyze the autooxidation of substituted phenols. Cu(II) complexes with a series of ethylene- diamine bearing N-alkyl substituents used to determine the effect of the number and type of alkyl groups on the activity of complexes in catalyzing the oxidation of phenols as well as the hp://cis.lanamres.net : dx.doi.org/cisxxxxxxxx Research Arcle Commun. Inorg. Synth. Kumar, R. et al./ Vol. 3, N°1 (2015), 9-15 9 Figure 1. ORTEP diagram of the complex with atom labelling scheme. http://dx.doi.org/10.21060/cis.2014.312